The present invention relates to fan blade molds, and relates more particularly to such a fan blade mold which can be conveniently adjusted to correct the balance of the fan blade to be molded.
Regular electric cooling fans for use with personal computers and other electronic apparatus are commonly comprised of an integral fan blade molded from plastics (see FIG. 1). If the fan blade is not balanced after its installed (see FIG. 2), it will cause noises. Various reasons will cause the fan blade to be unbalanced. These reasons include uneven material specific gravity, displacement of the fan blade metal shaft, deformation of the fan blade caused by heat and/or other factors, wearing of the fan blade mold, etc. Because the fan blade mold commonly uses two knock-out pins to knock out the fan blade when the fan blade is molded, the blades of the fan blade tend to be deformed when knocked out by the knock-out pins. Furthermore, because the shaft of the fan blade is made from metal, it must be installed in the mold during the molding of the fan blade so that the fan blade can be directly molded on the shaft. This procedure greatly complicates the production of the fan blade and increases its manufacturing cost. If the metal shaft is not accurately set in position, the fan blade will lose its balance when installed. If the unbalanced problem occurs, the fan blade mold must be modified. However, the procedure of modifying the fan blade mold is complicated and costly.